Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA.
Department of Physics, University of California, Berkeley, CA 94720, USA.
Science. 2020 Jul 3;369(6499):81-84. doi: 10.1126/science.abb0631.
Dielectric capacitors can store and release electric energy at ultrafast rates and are extensively studied for applications in electronics and electric power systems. Among various candidates, thin films based on relaxor ferroelectrics, a special kind of ferroelectric with nanometer-sized domains, have attracted special attention because of their high energy densities and efficiencies. We show that high-energy ion bombardment improves the energy storage performance of relaxor ferroelectric thin films. Intrinsic point defects created by ion bombardment reduce leakage, delay low-field polarization saturation, enhance high-field polarizability, and improve breakdown strength. We demonstrate energy storage densities as high as ~133 joules per cubic centimeter with efficiencies exceeding 75%. Deterministic control of defects by means of postsynthesis processing methods such as ion bombardment can be used to overcome the trade-off between high polarizability and breakdown strength.
介电电容器可以以超快速率存储和释放电能，并且在电子和电力系统中的应用得到了广泛研究。在各种候选材料中，基于弛豫铁电体的薄膜因其高能量密度和效率而受到特别关注，弛豫铁电体是一种具有纳米级畴的特殊铁电体。我们表明，高能离子轰击可以改善弛豫铁电体薄膜的储能性能。离子轰击产生的本征点缺陷可以降低漏电流、延迟低场极化饱和、增强高场极化率并提高击穿强度。我们展示了高达约 133 焦耳/立方厘米的储能密度，效率超过 75%。通过离子轰击等后合成处理方法对缺陷进行确定性控制，可以克服高极化率和击穿强度之间的权衡。
